Abstract: The position deviation after the continuous action of the hydraulic support in the fully-mechanized mining face affects the mining efficiency of the shearer. In view of the above problems, the mechanism of the hydraulic system of the fully-mechanized mining face is analyzed, the coupling relationship between the system pressure, flow and the displacement of the hydraulic cylinder is established, and a hydraulic cylinder precise displacement test platform with emulsion/pure water as the transmission medium is designed and built, which can carry out eccentric load and lateral load experiments of the test hydraulic cylinder. The test platform is composed of hydraulic test system, oil pressure regulation system, electrical control system, data acquisition system, upper computer software system, loading test bench, etc. The oil pressure regulation mechanism adjusts the working attitude of the hydraulic cylinder, the data acquisition system monitors and tests the pressure, flow, displacement, temperature and other data of the hydraulic cylinder in real time, and the loading test bench equates the hydraulic support, scraper conveyor and shearer as adjustable weight. Data acquisition frequency of the hydraulic cylinder precise control test system is 2 000 Hz, the nominal pressure is 31.5 MPa, the nominal flow is 400 L / min, the test hydraulic cylinder has a cylinder diameter of 100-240 mm, a stroke of 400-1 800 mm, and the working resistance is larger than 100 kN, which can achieve the working mechanism of the hydraulic cylinder under variable working conditions. When the system flow is 126 L/min, the displacement control error of the tested hydraulic cylinder is close to 20%; when the system flow is 50 L/min, the displacement control error of the tested hydraulic cylinder is stable within 7%. The experimental results show that the transient action of hydraulic cylinder extension and retraction can be ignored in the working process, and the displacement control error is mainly caused by the response delay of valve control components, and the control error increases linearly with the increase of system flow, which verifies the feasibility of the high flow rapid action and small flow precise regulation control scheme of the two speed pressure regulating valve. The hydraulic cylinder precise control test system is applicable to the research on the precise control of hydraulic cylinder and the coordinated control of hydraulic cylinder cluster, and provides an experimental method for realizing the precise control of hydraulic support in high-pressure and large flow fully-mechanized mining face.